The present invention relates to a system for a four-wheel drive vehicle convertible to two-wheel driving, and more particularly to a system for automatically changing the transmission from two-wheel drive condition to the four-wheel drive condition.
Sudden braking may cause dangerous slipping of the vehicle, which is caused by rocking of the wheels with brakes. In the four-wheel drive vehicle, since the front wheels and the rear wheels are connected with each other through the propeller shaft, either the front or the rear wheels are driven by the other wheels. Therefore, slipping of only the front or the rear wheels does not occur. This means that the four-wheel drive vehicle has a safe braking effect and safety in the steering operation.